Fixed optical devices linked to fixed color discriminators have been used in manufacturing to perform high-speed and highly accurate recognition of target surface colors. This equipment has been typically installed as part of an assembly line using rack mounted equipment and sensors. New optical discriminators allow photoelectric sensors to determine specific colors of the sensed surface unaffected by target gloss, light, and shading. However, such equipment has previously been limited by the size, mounting, and configuration of the sensors and color discriminators.
Equipment and systems, including aircraft that are exposed to the elements, often have their components or assemblages of components coated with corrosion inhibitor compounds. These compounds protect the equipment from the elements and are commonly sprayed on metal components to form a corrosion inhibiting surface. Because corrosion can lead to equipment damage, confirming the presence of corrosion inhibitor compounds on hard-to-reach surfaces is important.
Corrosion inhibitor compounds commonly are semi-translucent. The corrosion inhibitor compound adds a luster to a metal or primed surface that is reflective in a strong light and has a sticky surface tension that can be detected by touch. However, neither the appearance nor the feel of the surface can be inspected easily in hard-to-reach areas. On aircraft, these areas include areas such as the underside of stringers and frames.
The presence of corrosion inhibitor compounds in hard-to-reach areas has previously been checked by hand inspection utilizing a cotton swab. The swab, saturated with a solvent, is dabbed on the hidden area and then the swab is checked for discoloration showing corrosion inhibitor compound. However, this testing requires repair to the tested area. Alternately, to obtain proper coverage by corrosion inhibitor compound in hard-to-reach or hard-to-inspect areas, multiple layers of corrosion inhibitor compound are often applied to ensure that spray-over covers the areas where moisture can settle and corrode a joined surface.
Multiple applications of corrosion inhibitor compounds creates an added expense during manufacturing. Extra applications also add additional weight to the equipment through extra coating thickness and spray accumulation in collection areas. Multiple applications of corrosion inhibitor compound can result in coating thicknesses as much as ten times that required for corrosion protection. In aircraft, as well as other equipment where weight is a factor, multiple applications of corrosion inhibitor compound can result in a significant accumulation of inhibitor compound in bilge areas, increasing weight and thus lifetime equipment expense through increased fuel consumption.
Therefore, there is an unmet need in the art for a portable system for sensing the presence of coatings, especially corrosion inhibiting compounds, in hard-to-reach areas.